The basic principle underlying this proposal is that zinc is essential for normal membrane structure and function. We intend to examine the relationship of zinc to membrane composition in normal and malignant cells. First, we will extend our studies on zinc levels in serum, liver and tumor cells by measuring the concentration of zinc in subcellular fractions prepared from livers of zinc deficient mice as well as from livers and plasmacytoma cells of tumor bearing mice as a function of tumor growth. Second, we will determine any changes that occur in the lipid composition of serum and mitochondrial and microsomal membranes from liver and tumor cells as a function of diet and tumor growth. This will involve analysis of neutral and phospholipid classes as well as fatty acid composition. Third, we will determine the rate of synthesis and turnover of protein and lipid synthesis, rates of incorporation of lipid subclasses into mitochondrial and microsomal membranes and turnover rates of lipid and protein in these membrane fractions. We hope that these studies will contritube to the understanding of the exact role of zinc in membrane structure and function as well as the role of this trace metal in tumor growth.